Final answer:
This question is related to English and addresses the correct spelling of the word 'forty' and subject-verb agreement in a sentence.
Step-by-step explanation:
The phrase 'There was already fourty people there by the time we arrived' falls under the category of English because it presents an opportunity to discuss spelling conventions. The correct spelling for 'fourty' is forty, which is a common mistake made in English. Understanding the correct spelling of numbers and other words is an essential part of English language proficiency. When discussing countable nouns such as 'people', it is also important to use the correct subject-verb agreement; the phrase 'There was already forty people' should be 'There were already forty people'.